Emerging Challenges of GLP-1 Agonists in PET-CT Imaging

Recent research presented at the 38th Annual Congress of the European Association of Nuclear Medicine highlights a growing concern regarding the impact of GLP-1 receptor agonists on PET-CT scans used in oncology. These medications, widely prescribed for type 2 diabetes and weight management—seeing a 700% increase in usage in the U.S. between 2019 and 2023—can alter normal tracer uptake patterns, complicating image interpretation.

GLP-1 receptor agonists influence glucose metabolism, gastric motility, and sympathetic nervous activity. This leads to atypical FDG uptake in tissues such as skeletal muscle, the myocardium, and brown adipose tissue, which may mimic signs of malignancy or inflammation. A retrospective review by Alliance Medical Ltd. revealed several abnormal uptake patterns in patients taking these drugs, which could be misdiagnosed as pathological changes if medication history is not considered.

Dr. Peter Strouhal, Medical Director at Alliance Medical, emphasized the importance of recognizing these patterns. He explained that misinterpretation could cause unnecessary invasive investigations, incorrect cancer staging, and delays in treatment, adding stress to patients. Currently, there are no international guidelines in the UK addressing this issue. The team advises thorough documentation of medication histories but does not recommend stopping GLP-1 therapies before scans, aligning with Australian practices which include fasting and good glucose control.

The researchers plan to expand data collection to strengthen future guidelines and are fostering international collaborations to ensure consistent interpretation worldwide. Ultimately, awareness of these altered uptake patterns aims to improve diagnostic accuracy, reduce unnecessary procedures, and enhance patient care.

Source: https://medicalxpress.com/news/2025-10-glp-agonists-pose-emerging-pet.html